Method of manufacturing self developing photographic film units

ABSTRACT

Method of manufacturing a succession photographic film units each comprising rectangular photosensitive and second sheets secured in face-to-face relation by a combination mask and binding sheet formed with a rectangular exposure opening, secured to the outer surface of the second sheet and having marginal portions folded around the end and lateral margins of the photosensitive and second sheets and adhered to the lateral and at least one end margin of the photosensitive sheet. The film unit also includes a rupturable container of processing liquid mounted adjacent the trailing edge of the photosensitive sheet and having portions defining a liquid discharge passage coupled with the photosensitive and second sheets so as to direct the liquid contents of the container therebetween; and a trapping element secured between the trailing end marginal portion of the binding sheet and the trailing end portions of the photosensitive and second sheets for collecting and retaining excess processing liquid overrun. During the assembly process, the binding sheet is in the form of an elongate strip which functions as a carrier on which the other components of a succession of film units are mounted as the carrier is moved between and through a succession of work stations at which assembly operations are performed and the components of each film unit are checked for proper assembly. The binding sheet carries the succession of film units through substantially all assembly and inspection steps except for the last two assembly steps in which the lateral edge portions of the binding sheet-which extend transversely of the carrier strip-are folded and adhered to the photosensitive sheet.

United States Patent METHOD F MANUFCTURING SELF-DEVELOP- ING PHOTOGRAPHIC FILM UNITS Louis 0. Bruneau, Weston, Mass., assignor to Polaroid Corporation, Cambridge, Mass. Filed Apr. 20, 1971, Ser. No. 135,539 Int. Cl. B31f 5/00; B32b 31/04; G03c 3/00 U.S. Cl. 156-157 10 Claims ABSTRACT OF THE DISCLGSURE Method of manufacturing a succession of photographic film units each comprising rectangular photosensitive and second sheets secured in face-to-face relation by a combination mask and binding sheet formed with a rectangular exposure opening, secured to the outer surface of the second sheet and having marginal portions folded around the end and lateral margins of the photosensitive and second sheets and adhered to the lateral and at least one end margin of the photosensitive sheet. 'Ihe film unit also includes a rupturable container of processing liquid mounted adjacent the trailing edge of the photosensitive sheet and having portions defining a liquid discharge passage coupled with the photosensitive and second sheets so as to direct the liquid contents of the container therebetween; and a trapping element secured between the trailing end marginal portion of the binding sheet and the trailing end portions of the photosensitive and second sheets for collecting and retaining excess processing liquid overrun.

During the assembly process, the binding sheet is in the form of an elongated strip which functions as a carrier on which the other components of a succession of film units are mounted as the carrier is moved between and through a succession of work stations at which assembly operations are performed and the components of each film unit are checked for proper assembly. The binding sheet carries the succession of film units through substantially all assembly and inspection steps except for the last two assembly steps in which the lateral edge portions of the binding sheet-which extend transversely of the carrier strip-are folded and adhered to the photosensitive sheet.

The present invention is concerned with a novel and improved method of fabricating and assembling a succession of self-developing photographic film units particularly of the type described, for example, in the copending U.S. patent application of Edwin H. Land et al., Ser. No. 5,799 filed Ian. 26, 1970, now U.S. Pat. No. 3,619,192; and in U.S. Pat. Nos. 3,415,644; 3,415,645; 3,415,646; 3,473,925; 3,576,626; 3,578,540; 3,594,164 and 3,594,165. A film unit of this type includes all of the materials and components required to produce a photographic print, preferably in full color, by a diffusion transfer process. The basic components of the film unit are a first or photosensitive sh'eet including a layer `of a light sensitive image-recording material such as silver halide ga second or image-receptive sheet superposed with the photosensitive sheet and adapted at least to aid in the distribution of a liquid processing composition between the sheets in contact with an exposed area of the photosensitive sheet and preferably, to serve as a support for a visible image formed by diffusion transfer, a rupturable container of a viscous liquid processing composition adapted to unidirectonally release the processing liquid in response to hydraulic pressure generated within the liquid by the application of compressive pressure to the container; a combination mask and retaining sheet for defining the image area and retaining the various components of the film unit together; and trapping means for collecting and retaining excess processing liquid overrun.

ice

The photosensitive and second sheets of the preferred form of film unit described herein are rectangular, of equal width but of unequal length, the second sheet being substantially longer than the photosensitive sheet so that the ends of the second sheet extend beyond the ends of the photosensitive sheet. The two sheets may be held in faceto-face relation by the combination mask and binding sheet which includes a rectangular exposure opening and is adhered to the outer surface of the second sheet. Alternatively, the photosensitive and second sheets may be laminated to one another prior to being brought into association with the combined mask and binding sheet. The second sheet is preferably transparent to permit exposure of the photosensitive sheet therethrough and the mask sheet is preferably light opaque and white so as to provide an aesthetically pleasing border around the visible image formed between the sheets and visible through the transparent second sheet. The margins of the mask sheet are folded around the end and lateral edges of the second sheet and are adhered to the trailing end and lateral margins of the photosensitive sheet for retaining the two sheets in face-to-face relation. The trapping means preferably take the form of a spacing element confined between the trailing end margins of the photosensitive and second sheets and the marginal portion of the mask adhered to the photosensitive sheet adjacent at its trailing end. The rupturable container of processing liquid is mounted on the leading end portion of the second sheet which extends beyond the leading edge of the photosensitive sheet by a distance slightly in excess of the shorter dimension of the rupturable container and is retained in place by marginal portions of the mask sheet, folded around the lateral and leading end edges of the second sheet and adhered to the margins of the container. A narrow sealing strip is secured to the outer surface of the photosensitive sheet overlapping the leading edge of the photosensitive sheet and a margin of the container to which the sealing strip is secured and cooperates with the second sheet to provide a passage for conducting the processing liquid from the container between the photosensitive and second sheets at the leading edge of the photosensitive sheet.

Obviously a film unit of this type constitutes a complex structure requiring a large number of fabrication, assembly and inspection operations which in order for manufacture to be economically feasible, must be performed in rapid sequence by machinery that is substantially automatic in its operation. The present invention has an object, the provision of a novel and improved film assembly process which makes possible the fabrication, assembly, and inspection of a large number of individual film units of the type described, by machinery which is substantially automatic in its operation.

Another object of the invention is to provide a film manufacturing method of the type described in which a component common to a succession of individual film units in the fabrication and assembly process functions as a carrier for transporting the individual film units through a sequence of fabrication, assembly and inspection operations.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the method involving the several steps and the relation and order of one or more of such steps with respect to each of the others which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings:

FIG. 1 is a somewhat schematic, perspective view illusvarious fabrication, assembly and inspection stations at which the components of the succession of film units are assembled to form film units each having its longitudinal dimension extending in a direction transverse to the length of strip 40.

Strip 40 which forms a succession of binding sheets 18 is of substantial length, i.e. hundreds of feet, and has a width equal to the overall length of each binding sheet. It may be in coiled form and provision may be made for splicing the trailing end of a strip to the leading end of the next succeeding coil of strip 40 without interrupting the fabrication and assembly operation. The first operation performed on strip 40 as part of the fabrication and assembly process illustrated in FIG. 1, is a cutting operation in which the rectangular exposure opening 28 is formed and notches 42 and 44 are formed in the opposite lateral margins of strip 40 to prevent overlap and excessive thickness in the regions in which the mask sheet is folded around the edges of the image-recording sheet during subsequent assembly operation. The cutting operation may be performed by conventional means such as a punch and die.

Although the photosensitive and second sheets 12 and 14 may be brought into the assembly operation as separate, elongated strips, in the preferred embodiment illustrated, the photosensitive and second sheets (strips) are also supplied in the form of coils having widths equal to the lengths of the respective sheets and are laminated to one another prior to being brought into association with strip 40. The laminating process essentially comprises guiding the photosensitive and image-receiving sheet along converging paths into superposed relation, distributing a laminating liquid between the sheets and pressing them into face-to-face contact. For this purpose, a pair of laminating rollers 46 and 48 may be employed for advancing the sheets therebetween into face-to-face contact and pressing the sheets together with a nozzle 50 for introducing the laminating liquid between the sheets at the nip of rollers 46 and 48. Inasmuch as the photosensitive and imagereceiving sheets include facing surface layers formed of water soluble polymeric materials, e.g. gelatin and polyvinyl alcohol, the laminating liquid preferably includes Water which may contain a water soluble polymeric filmforming material adapted to assist in forming an easily rupturable bond between the sheets. For specific examples of such materials and methods of laminating the photosensitive and image receiving sheets, further reference may be had to the copending U.S. patent application of Albert J. Bachelder et al., Ser. No. 744,912, filed July 15, 1968, now U.S. Pat. No. 3,652,281.

The assembly process begins with the bringing together of the laminate comprising the photosensitive and imagereceiving sheets, and carrier strip 40 and adhering the laminate to the carrier strip which thereafter functions to transport sections of the sheets (laminate) as Well as the other components of the film units through subsequent fabrication, assembly and inspection operations. As shown in FIG. l, the carrier strip 40 is moved upwardly over a guide 52 and then along a generally horizontal path through a succession of machine stations in which the assembly and inspection operations are performed. The laminate comprising photosensitive and second sheets 12 and 14 is advanced by suitable means such as a pair of rollers 54 and 56 into superposition with strip 40 at guide 52. The laminate is advanced from between rollers 54 and 56 between a knife 58 and anvil 60 operative to cut the laminate transversely to form a leading end edge normal to the lateral edges of the laminate. Both carrier strip 40 and the laminate are advanced into superposition such that the leading edge designated 62 of the laminate is located approximately one quarter of the distance from an edge of an exposure opening 28 in strip 40 and the adjacent edge of the preceding exposure opening.

In the assembly process, strip 40 may be moved either continuously or intermittently, the latter method being illustrated in FIG. l, and motion of strip 40 and the section of the laminate are arrested with the leading edge margin of the laminate, located with respect to strip 40 as previously indicated, disposed between the jaws, one of which is shown and designated 64, of a heat sealing device adapted to apply heat and compressive pressure to strip 40 and the laminate to bond the leading edge portion of imagereceiving sheet 14 to strip 40. For this purpose, the upper surface of strip 40 is coated with a conventional heat activated adhesive formed, for example, of a thermoplastic polymer. Carrier strip 40 is then advanced to a second heat sealing station including a pair of juxtaposed jaws one of which is shown and designated as 66, for sealing the image-receiving sheet to carrier strip 40 in the region completely surrounding the exposure opening 28 in the carrier strip. Subsequent to adhering the leading edge portion of the laminate to strip 40 at the heat sealing station including jaw 64 and prior to or during movement of the strip and laminate into the second heat sealing station including jaw 66, knife 58 is actuated to severe the laminate to the desired length and the strip is caused to advance a greater distance than the laminate to provide spacing between the trailing edge of the section of the laminate severed from the remainder of the laminate and the new leading edge of the laminate formed by actuation of knife 58. This motion is suflicient to locate the leading edge 62 of the laminate with respect to strip 40 as previously described and between the heat sealing jaws of the first heat sealing station. Thus the process is basically one of heat sealing the laminate to the carrier strip, advancing the carrier strip so as to move the laminate heat sealed thereto toward the leading edge, severing the laminate to length and then advancing the next succeeding leading end portion of the laminate into position with respect to strip 40 to be heat sealed.

The primary reason for preferring prelamination of the photosensitive and second sheets, at least insofar as the manufacturing and assembly processes are concerned, will be apparent at this point. In the initial heat sealing operation, it is a section of the image-receiving sheet which is attached to the carrier strip so if the photosensitive sheet were not laminated to the image-receiving sheet, provision would be required for at least temporarily attaching the photosensitive sheet to the image-receiving sheet which is in turn attached to carrier strip 40. In a manufacturing process in which the photosensitive and image-receiving sheets are not prelaminated by distribution of a laminating liquid, they may at least be temporarily attached to one another by heat sealing jaws located adjacent knife 58, preferably ahead of the knife and adapted to soften and bond to one another portions of the facing polymeric layers of the two sheets in regions which are located near the margins of the sheets in the completed film unit.

At the next station or stations in the film assembly app aratus, a container 16 is attached to an end lateral marglnal portion of strip 40 which comprises leading end .section 30 of mask sheet 18 and a trapping element 20 1s mounted on a marginal section of strip 40 which comprises a trailing end section 32 of mask sheet 18. The container 16 is attached by heat sealing the longitudinal margln of the container located opposite the rupturable longitudinal seal, by gripping the leading end section 30 and'the margin of the container between a pair of heat sealmg jaws. Trapping element 20 is similarly mounted at the opposite edge of strip 40 by compressing the element and trailing end section between a pair of heat sealing jaws. The trapping element may take the form of an elongated strip or web severed from the remainder thereof immediately prior to or subsequent to adherence by heat sealing to carrier strip 40.

Each container 16 may be formed as one of a succession of containers produced by a continuous process and severed from a strip of containers by a knife and anvil 68 and 70 immediately prior to or subsequent to heat healing of the container to carrier strip 40. In the embodiment shown in FIG. 1, sealing strip 22 is heat sealed to a longitudinal marginal section 36 of container 16 prior to severance of the container from the remainder of a strip of containers. Sealing strip 22 may also take the form of an elongated, coiled strip and heat sealing thereof to the strip of containers may be either a continous or an intermittent operation performed by compressing the containers and strip 22 between a pair of heat sealing members one of which is shown as jaw 72 in FIG. 1. In this manner both sealing strip 22 and a container 16 are severed simultaneously and to the same length. As is previously noted, this may be accomplished either subsequent to or prior to adherence of the container to a margin of strip 40.

The next operations in the fabrication and assembly process are folding operations in which the leading end section 30 to which a container is attached and the trailing end section 32 to which a trapping element 20 is attached, are folded through 180 so that the container is brought into face-to-face relation with the leading end section 24 of the image-receiving sheet and the trapping element is brought into face-to-face relation with the trailing end sections of the photosensitive and imagereceiving sheets and is confined between the trailing end sections and trailing end section 32 of sheet 18. The folding operations may be accomplished by conventional means such as plows and/or movable fingers such as are well known in the art.

The next assembly operations involve the heat sealing of strip 22 to the leading margin of photosensitive sheet 12 and the heat sealing of trailing end section 18 to the photosensitive sheet near the trailing edge thereof. These heat sealing operations are accomplished by conventional means in the same manner as the previously described heat sealing operations, namely by compressing the sheets to be sealed to one another between a pair of heated jaws. Heat sealing of strip 22 and trailing end section 32 to the outer surface of the photosensitive sheet complete the assembly operations in which a succession of film units, in -various stages of assembly and fabrication are coupled to one another and transported by carrier strip 40.

The fabrication and assembly apparatus will also include a number of inspection stations which serve to insure that each successive fabrication and assembly operation has been performed correctly. These inspection means will include means adapted to determine, for example, whether or not the laminated and photosensitive and image-receiving sheets are properly aligned with strip 40; that the leading edge of each section of the laminate is properly located with respect to an exposure aperture; that trapping element 20 is attached to the carrier strip and is properly located thereon; that a container and heat sealing strip 22 are attached to the carrier strip and properly located thereon; and that the various folding and sealing devices have performed as required. Such inspection means are well-known in the art and include mechanical, optical and pneumatic devices for sensing the presence and/or location of the various components. The purpose of providing continuous monitoring of the fabrication and assembly process is to promptly identify improperly fabricated or assembled film units immediately following the particular fabrication or assembly step being monitored so that action can be taken to correct the operation which is resulting in the defect and to promptly identify the defective film unit so that successive assembly operations are not performed thereon and components wasted, and the film unit will be rejected or set aside for salvage of components and/or further remedial work at a subsequent stage in the manufacturing process.

Following heat sealing of the leading and trailing end sections 30 and 32 to the photosensitive sheet, the succession of film units carried by strip 4() is advanced between a knife 74 and anvil 76 which cooperate to sever strip 40 substantially midway between the trailing edge Of the laminated photosensitive and second sheets of one film unit and the leading edge of the laminate of the next succeeding film unit. At this stage in the process, the individual film units are then transported by a carrier which is part of the assembly machine and transports the lm units through at least two more work stations. In the lfirst, lateral marginal sections 34 are folded and in the second station, sections 34 are heat sealed to the lateral margins of photosensitive sheet 12. During these last two steps, the film units are preferably advanced in a direction transverse to their previous direciton so that folding may be accomplised by conventional means such as plows and/or fingers and the heat sealing steps may be performed either continuously as by advancing the margins of each film unit between pairs of heat sealing rollers, or intermittently by clamping the margins between heat sealing jaws two of which are shown in FIG. l and designated 78.

Upon completion of this last operation, the assembly of each film unit is complete and following a final inspection the lm unit is ready to be loaded separately or together with other lm units into a suitable lighttight container or cassette in which it is exposed within a camera.

As will be seen from the foregoing the invention provides a novel method of fabricating and assembling a self-developing, photographic film unit of the type comprising a multiplicity of components. An important feature of this method is the use of a component common to a succession of film units as a carrier for supporting and transporting the film unit components through most of a succession of fabrication, assembly and inspection operations, which are part of the manufacturing process, thus eliminating the necessity for expensive machinery for transporting a succession of film units through a series of machine stations at which the various fabrication, assembly, and inspection operations are performed. The use of a common component in the form of an elongated strip not only simplifies the transport machinery required, but materially contributes to the ability to perform the fabrication, assembly and inspection operations in rapid sequence in a machine that is automatic in its operation to produce a large number of film units having close dimensional tolerances while eliminating a large portion of waste normally associated with such assembly operations.

Since certain changes may be made in the above process without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. 'I'he method of manufacturing a photographic film unit comprising, in combination:

forming a succession of substantially equal-sized, uniformly spaced openings in an elongated rst strip of sheet material, said openings being separated by transverse sections of said first strip;

locating a first leading edge of at least a second elongated strip of sheet material in face-to-face relation with a transverse section of said 4first strip intermediate adjacent openings therein;

securing said leading edge of said second strip to said transverse section of said first strip between said openings; severing the leading end section of said second strip to a length slightly longer than the lateral dimension of one of said openings in said first strip; and

securing said severed leading end section of said second strip to said first strip throughout an area surrounding the opening in said first strip.

2. The method of claim 1 wherein a second and succeeding leading end sections of said second strip are each sequentially secured to said first strip, severed from the remainder of said second strip, and secured to said -iirst strip throughout an area surrounding one of said openings.

3. The method of claim 1 wherein said second strip is secured to said first strip with said leading edge of said second strip located to overlap approximately one quarter of said transverse section between adjacent openings in said tirst strip.

4. The method of claim 2 wherein a rupturable container of liquid is coupled with said first and second strips along a lateral edge thereof.

5. The method of claim 4 wherein said leading end section of said second strip is secured to said transverse section of said first strip with a lateral portion of said first strip extending beyond a lateral edge of said end section of said second strip and said lateral edge portion of said first strip is folded around said lateral edge of said end section of said second strip and then adhered to the surface of a section of said second strip.

6'. The method of claim 5 wherein said second strip comprises at least two strip elements adhered in faceto-face relation by a liquid distributed therebetween during movement thereof into superposed relationship, said liquid being distributed in contact with at least a major portion of the facing surfaces of said strip elements and producing a bond weaker than the bond between any other layers comprising said second strip.

7. The method of claim 6 wherein said first strip is light opaque, and said second strip elements comprise, in order from said first strip, a light-transmitting element 10 and a light opaque element which includes at least one layer of a light-sensitive image-recording material.

8. The method of claim 7 wherein a spacing element is attached to the lateral edge portion of said first strip opposed to said rupturable container prior to folding and adherence of said lateral edge portion of said -first strip to said second strip.

9. The method of claim 8 wherein said rst strip is severed at said transverse section midway between the spaced transverse edges of adjacent end sections of said second strips to form individual lm units.

10. The method of claim 9 wherein said transverse portions of said first strip, following severance thereof, are folded around said transverse leading and trailing edges of each of said end sections of said second strips and then adhered to the surface of a section of each of said end sections of said second strips.

References Cited UNITED STATES PATENTS 3,619,192 11/1971 4Land 96-3 X 2,543,181 2/1951 Land 96--3 X 3,152,515 10/1964 Land 206-56 A A 2,634,886 4/1953 Land 206-56 A A 2,819,656 1/ 1958 Patterson 156-263 X PHILIP DIER, Primary Examiner U.S. Cl. X.R.

M. FREEMAN Aug. 14, 1973 RESILIENT STRIP MOUNTING FOR PLASTIC BAG FABRICATOR Filed April 23, 1971 35 F/G. a

.INVENTOR MAX FREEMAN BY MMlppwqw 

